US Bridges

County Road Bb over Alamosa River

Fair

Conejos County, Colorado · 4.7 MI W of CR 6 · Structure no. CON11.5W-17.1NA

Built
1989
36 years old
Condition
Fair
inspected March 2025
Type
Tee Beam
Prestressed Concrete
Length
54 ft
1 main span
Daily traffic
30
2022 count
Owner
County
County Highway Agency

About this bridge

County Road Bb over Alamosa River is a prestressed concrete tee beam carrying County Road Bb over Alamosa River in Conejos County, Colorado. It was built in 1989, so it is 36 years old, younger than the Colorado average of 42.2 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 6 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

It carries about 30 vehicles a day, projected to reach 35 by 2042. The structure is 54 ft (16.5 m) long and 29 ft wide. If it were closed, the detour would be 6.8 mi (11 km).

Location

Open in Google Maps
CarriesCounty Road Bb
CrossesAlamosa River
Location4.7 MI W of CR 6
RouteCounty Highway 0
CountyConejos County
StateColorado
Coordinates37.33158, -106.23059
Functional classRural Local

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionMarch 2025
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment4: Meets minimum tolerable limits to be left in place as is
Operating rating73.2 US tons
Inventory rating43.9 US tons

Structure

Structure typeTee Beam
MaterialPrestressed Concrete
DeckOther
Main spans1
Design loadHS 20
Structure length54 ft (16.5 m)
Longest span51 ft (15.4 m)
Deck width29 ft (8.7 m)
Roadway width26 ft (7.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic30 (2022)
Projected traffic35 by 2042
Trucks0%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed6.8 mi (11 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was County Road Bb over Alamosa River built?

It was built in 1989, making it 36 years old in 2025.

What condition is County Road Bb over Alamosa River in?

The National Bridge Inventory rates it in fair condition. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. The last reported inspection was in March 2025.

How much traffic does County Road Bb over Alamosa River carry?

About 30 vehicles per day (2022 count).

How long is County Road Bb over Alamosa River?

The structure is 54 ft (16.5 m) long with a longest span of 51 ft (15.4 m) and a deck 29 ft wide.

Who owns County Road Bb over Alamosa River?

It is owned by the County Highway Agency.